Late Cretaceous and Paleogene freshwater gastropods from Northeastern Mexico

Abstract

Twenty-three species of Campanian, Maastrichtian, Paleocene, and Eocene freshwater gastropods from northeastern Mexico are described, including eight new species:Viviparus mcbridei, Pachychilus(Pachychiloides)lawtoni, Melanoides(Melanoides)yolandae, Melanoides(Melanoides)wollebeni, Physa cepedaensis, Mesolanistes magnus, Mesolanistes murrayi, andGyraulus zoltani.Specimens were collected from fine-grained, green sandstone and mudstone, red mudstone, and as hematized remains in fine light-brown sandstones belonging to the following stratigraphic units of northeastern Mexico: Cerro del Pueblo (Campanian, Parras Basin), Olmos (Maastrichtian, Sabinas Basin), Las Encinas (Paleocene, Parras Basin), and Carroza (Eocene, La Popa Basin) Formations. All except two of the genera (?PyrguliferaandMesolanistes) have recent representatives. Review of habitats of living species of the six extant genera and interpretations of sample lithologies support the inference of dominantly freshwater paleoenvironments. Only one Maastrichtian locality is interpreted confidently to have had a brackish water influence.

Hemipelagic cephalopods from the Maastrichtian (late Cretaceous) Parras Basin at La Parra, Coahuila, Mexico, and their implications for the correlation of the lower Difunta Group

“…Vega et al, 2007;Perrilliat et al, 2008), few biostratigraphic data exist from the late Cretaceous, mainly due to the absence of biostratigraphic marker fossils. For instance, planktonic foraminifers are absent in these near-coast environments, and ammonoids are mostly represented by endemic species, specialized to these extreme non-pelagic environments (Wolleben, 1977;Vega-Vera and Perrilliat, 1990;Ifrim et al, 2005).…”

Eocene Bursera (Burseraceaea) in La Carroza Formation, Mexico: a dry tropical flora member

“…comm., 2007). The studied section consists of bioturbated siltstone and fine to medium-grained, lenticular or cross stratified sandstone deposited in alluvial environments, as suggested by the presence of Pachychilus lawtoni Perrilliat, Vega, Espinosa and Naranjo-García (Perrilliat et al, 2008).…”

Aplicación de fotogrametría digital para el registro de las huellas de dinosaurio de la Formación Cerro del Pueblo (Campaniano tardío), Coahuila, México

“…De acuerdo con Eberth et al (2004), esta formación representa una unidad transicional que destaca por la gran diversidad de organismos fósiles que contiene, entre los que se incluyen plantas, protistas, invertebrados y vertebrados, organismos que vivieron en condiciones marinas, salobres y terrestres (RiveraSylva et al, 2006;Gates et al, 2007;Perrilliat et al, 2008;Loewen et al, 2010; Bravo-Cuevas y Rodríguez-de la Rosa, 2014). Eberth et al (2004) ubicaron a la FCdP entre las magnetocronozonas 32n.3r-32n.2n, sugiriendo una edad absoluta máxima de 72.5 millones de años (Campaniano tardío).…”